Synthetic dyes based on environmental considerations. Part 2: Iron complexes formazan dyes

Dyes and Pigments, Vol. 30, No. 1, pp. 1-20, 1996 Elsevier Science Ltd Printed in Great Britain 0143-7208/96 $15.00 + 0.00 ELSEVIER

0143-7208(95)

00048-8

Synthetic Dyes Based on Environmental Considerations. Part 2: Iron Complexed Formazan Dyes* Jolanta Sokolowska-Gajda,t Harold S. Freeman:~ & Abraham Reife Department of Textile Engineering, Chemistry, and Science, North Carolina State University, Raleigh, NC 27695-8301, USA (Received 2 May 1995; accepted 9 June 1995)

ABSTRA CT This paper is concerned with the synthesis and evaluation of some 1:2 iron complexed formazan dyes for use on wool and nylon. The chemical structures of these new dyes were confirmed with the aid of negative ion FAB mass spectrometry, a technique which also proved instrumental in establishing the nature of the products obtained when unsymmetrical 1"2 iron complexed formazan dyes were synthetic targets. It is clear from the fastness properties obtained that certain of the title compounds could have utility in applications requiring high lightfastness.

INTRODUCTION

It is evident from the open literature that manufacturing and application processes involving the treatment of metallizable dyes with Co(II), Cr(III) and Cu(II) ions (each of which is considered to be a priority pollutant by the US Environmental Protection Agency) have become areas of considerable concern in the associated industries. Interestingly, little has been published about the suitability of iron complexes as environmentally friendly alternatives to currently used Cr(III) and Co(II) metal complexed acid dyes for wool and nylon. Although iron complexes of azo dyes (1:1 and 1:2 type) have been claimed in the patent literature, they are not * Part 1 published in Textile Research Journal. t Permanent address: Institute of Dyes, Technical University (Politechnika), Lodz, Poland. $ Corresponding author.

2

J. Sokolowska-Gajda et al.

often used in the coloration of textile fibers. Perhaps their lack of use as textile dyes can be traced to the general belief that iron complexed azo dyes are inferior in fastness to Cr and Co complexed azo dyes and usually produce olive-brown, brown, and black-brown shades on the fabric. As a part of continuing research t,2 aimed at developing an approach to synthetic dyes based on toxicological considerations, a group of iron complexed formazan dyes was synthesized as potential alternatives to certain Co and Cr metallized acid dyes used at present. Historically, formazans have been used in a number of different areas. For instance, because they produce very fast and intense color reactions with many metal ions they are often used as analytical reagents. Since water-soluble, colorless tetrazolium salts can be reduced to water-insoluble, deeply colored formazans, they have found practical application as bioindicators in biochemistry and cytochemistry. Also, the conversion of tetrazolium salts into metallized formazan dyes is used in color photography. Water-soluble formazan complexes containing sulfonamide, alkylsulfonyl or sulfonic acid groups possess a high affinity for protein and polyamide fibers, and can be used for dyeing or textile materials. An example is CI Acid Black 180 (1). The patent literature provides a few examples of 1:2 metallized formazan dyes. 3~ All of them are 1:2 Co complexed formazan compounds and are used for dyeing protein and polyamide fibers from neutral or weakly acidic baths. Some of them 7 are used separately or in combination with

© /c~ N

N

N

XXC/

N

©

_O

Iron complexed formazan dyes

3

other dyes and are recommended for dyeing leather. 8 The most important formazan dyes are the 1:1 Cu complexed formazan reactive dyes used for dyeing and printing cellulose fibers. The largest group of these dyes is derived from cyanuric chloride 9-t5 or cyanuric fluoride. 16'17 Some o f the formazan reactive dyes also contain 5-chloro-2,4,6-trifluorpyrimidine 27-2~ as the reactive system. A large n u m b e r of the formazan reactive dyes _O

0

/c~ N

m

.,e N

N C

0 D~e

X

XI

Y

Y1

2b

O

O

3b

0

O

C1

CI

SO2NH2 80~'qI-I2

413

0

O

NO2

NO2

SO2NH2 80~1H2

5b

O

0

H

H

S O z N H 2 SOzNHz

61>

COO

COO

H

H

SO~NHs ~ 2

7b

0

O

C!

CI

SO:gq'a

SOsNa

8b

O

0

NO,2

N0~

S03Na

SOaNa

9b

COO

COO

H

H

80~a

SOsNa

10

O

O

SO2NH~

H

H

11

O

O

S02NI-12

C]

H

SOzNHz S02NH2

12

O

0

H

CI

S02NH 2

SOtNHz

13

0

0

NOz

CI

S02NHz

SOzNH2

14

0

0

NO2

C!

SO~a

SO~la

SO~,NH2 SOsNH2

Z

ZI

H

H

Fig. 1. Dyes prepared and evaluated in this investigation. Dyes 10-14 are statistical mixtures of unsymmetrical and symmetrical molecules, though not specifiedhere.

4

J. Sokolowska-Gajda et al.

contain a vinylsulfonyl group, 22 26 sometimes also in combination with cyanuric chloride which affords bifunctional reactive dyes. 27,28 The patent literature also contains examples of 1:1 Cu or Ni complexed formazan disperse dyes for dyeing polyamide fibers, 29-32 and water-soluble metal complexed formazan cationic dyes for dyeing polyacrylonitrile fibers. 33 Iron is also claimed as one of the metals used for metallization. 33 The focus of the present paper is the synthesis of dyes 2-14, and the determination of their fastness properties. The dye structures are shown in Fig. 1.

RESULTS AND DISCUSSION The target iron complexed formazan dyes were prepared in the manner outlined in Figs 2 and 3. The unmetallized dyes were prepared by conventional diazotization of either 2-aminophenol derivatives or anthranilic acid followed by coupling with either benzaldehyde phenylhydrazone, benzaldehyde phenylhydrazone-4-sulfonamide, or benzaldehyde phenylhydrazone-4-sulfonic acid in aqueous pyridine. Benzaldehyde phenylhydrazone-4-sulfonamide and its 4-sulfonic acid analog were synthesized via the condensation of benzaldehyde with phenylhydrazine-4-sulfonamide or o.

2a, Y= SO2NH2

OH ..NH~ NJWO.~,' MCl=

~ , ~ S O , NH,

ClB

Y

x_

~ . ct 411. ~ 2 5aoH

Y 7B, CI h . No~ ~

"NH2N4dW(~I HCI:

CIO

.

.oC ~. b.

Fig. 2.

Z S%NH2 Sos~

Synthesis of symmetric dyes 2-9.

Iron complexedformazan dyes

5

10 ~N

11

~ . / N = N --C~N

0C y•N=N•

FeS04

"VO

--

12 14

Y

Z

Vl

Zl

2a

S02NH 2

H

5a

H

SO2NH 2

2a

SO2NH2

H

3a

CI

SO2NH 2

5a

H

SO2 N H2

3~

CI

SO 2 N H 2

4~

NO 2

SO2 NH2

3a

CI

SO2 N H2

88

NO 2

SO 3 Na

7a

cI

s o 3 Na

Fig. 3.

Synthesis of asymmetric dyes 10-14.

phenylhydrazine-4-sulfonic acid. The latter two compounds were obtained by reduction of the corresponding diazonium salts with Na2SO3. 34 The target symmetric dyes (Fig. 2) were synthesized in high yield and purity by the conversion of unmetallized formazan dyes to their 1:2 Fe complexes using FeSOa-H20 at pH -- 7 and 60-70°C. Using two molecules of different formazan dyes (Fig. 3) and the same metallization conditions, the 100

80

60 84P 4~

28'

459 [

34I

. L,~

• ,.t i

4110

6@0 Fig. 4.

8@~

FABmass spectrum of dye 2b.

918 .L

'i |

MIZ

6

J. Sokolowska-Gajda et al.

synthesis of unsymmetrical dyes was attempted. However, the products obtained were statistical mixtures of the target unsymmetrical and corresponding symmetrical dyes. The chemical structure of each unmetallized and metallized dye prepared in this investigation was verified using negative ion FAB mass spectrometry. Although FAB spectrometry is known to be an effective ionization procedure for a number of non-volatile hydrophilic d y e s , 35-37 papers published so far do not demonstrate the suitability of this technique for generating molecular weight information on formazan dyes and their 1:2 medially complexed analogs. In most cases, 3-nitrobenzyl alcohol was used as the matrix. 38-39 In the case of unmetallized dyes containing sulfonic groups, diethanolamine was found to be more useful than 3-nitrobenzyl alcohol. In the spectra of the dyes investigated, we detected the molecular ion M: and/or the pseudomolecular ion [M--Na] formed by the loss of a sodium cation from either a sulfonate moiety or a counterion of 1:2 Fe complexed dyes. In the case of unmetallized dyes, the [M--H] ion was usually observed. The relative abundances of the molecular ions are summarized in Table l, while examples of the spectra recorded are given in Figs 4-7. It is worthwhile to note that in the FAB spectra of formazan dyes containing sulfonic groups the spectra were characterized not only 100" R e

1 a

t i

80.

U

B98

e

A b

60.

U tl

d a

921 40.

n c e

385 20 I

378

476

IJ,iiilkHalki}i,,,

6i9

742

956

i

488 M/Z

Fig. 5.

FAB mass spectrum of dye 6b.

Iron complexed formazan dyes 100

153 1 9

7

~ 16

R e

1 a t

BO

i V e

A 60 b

842

U n

d a 40 n c e

20

1iiI ,

910

426

352

, L,.;ii L~I,.LLL:~:,, , 200

Fig. 6.

580

,~__I.

811 i

600

41~0

800

1000 M/Z

FAB mass spectrum of dye ll.

100' P e

]

a

t. 80 1 V e

A b 60 U rl

440

Z53

d a

275

n 40 C e

46~

301

319

20

~o ....

237 I

/

2;~ . . . .

300 . . . .

3;0 . . . .

4~o . . . .

4so . . . .

s~o . . . .

5so

M/Z

Fig. 7. FAB mass spectrum of dye $a.

8

J. Sokolowska-Gajda et al.

by [M--H]- and [M--Na] ions but also by key daughter ions that were important in establishing the structures involved. To confirm which fragments originate directly from [M--Na] ions, B/E linked scanning with collisional activation 4° was carried out using this type of species as the parent ion. As an example, the B/E linked scan of the [M--Na] ion of dye 8a is reported (cf. Fig. 8), which confirmed the formation of the fragments shown in Fig. 9. FAB mass spectrometry was also very useful in explaining the interesting behavior of Fe metallized formazan dyes observed during their synthesis. Surprisingly, we found that the synthesis of pure unsymmetrical 1:2 formazan dyes by the reaction of a 1:1 Fe complexed dye with a structurally different unmetallized formazan dye was unsuccessful, in that the isolated product was a mixture of three different 1:2 metallized dyes. In addition, we found that heating a mixture of the two symmetrical 1:2 Fe formazan dyes 45 and 5b under conditions identical to those normally employed in the synthesis of 1:2 Fe formazan dyes afforded the unsymmetrical product mixture 13 (m/z 921) again (Fig. 10). This provides evidence for the interchange of dye molecules under the aforementioned conditions, and explains our difficulties with the stepwise synthesis of pure unsymmetrical 1:2 Fe formazan dye. The synthesized formazan dyes were applied to nylon and wool fabric R e

I 30.

a

t i v 25. e

A b 20, U n

d a 15

301

N C e

I

I LTz

I

10

100

200

300

400 M/Z

Fig. 8.

B/E linked scan of dye 8a.

Iron complexed formazan dyes

TABLE 1 Relative A b u n d a n c e a o f M o l e c u l a r I o n Species in the F A B M a s s Spectra o f 1:2 Fe Metallized Dyes

Dye 2a 2b 3a 3b 4a 4b 5a 5b 6a 6b 7a 7b 8a 8b 9a 9b 10 11

12

13

14

Assignment

m/z

Relative abundance

[M [M [M [M [M [M [M [M]M M M]: M M M M M M M]M M M M M M 2b 3b [M 5b 3b [M 4b 3b [M -

394 842 428 911 439 932 394 865 842 422 921 898 429 451 958 462 440 956 978 423 445 922 842 876 842 910 876 842 910 921 932 910 967

50.94 44.44 100.00 b 14.17 35.42 12-04 100.00 4.20 27-81 100.00" 42.15 b 65.19 57.57 u 30-95 3.89 ~ 50.50 -1 55-49 5.62 e 6.87 82.67 f 79.60 11.11 71.40 100.00 50.00 15.00 40.00 19.75 27.00 62-03 100.00 27.00 13.05

H] Na] H] Na] H] Na] H] Na] H] Na] Na] H] Na+H] H] Na] Na+H] 2Na+H] Na] 2Na+2H] Na] Na]

Na]

Na]

Na+H]

" I o n a b u n d a n c e s are expressed relative to the base peak m/z -- 152 (3-nitrobenzyl alcohol, 100%) unless otherwise indicated. h I o n a b u n d a n c e s are expressed relative to the base peak m/z -- 306 (3-nitrobenzyl alcohol, 30%). c Ion a b u n d a n c e s are expressed relative to the base peak m/z = 152 (3-nitrobenzyl alcohol, 80%). a I o n a b u n d a n c e s are expressed relative to the base peak m/z = 104 (diethanolamine, 100%). e Ion a b u n d a n c e s are expressed relative to the base peak m/z = 306 (3-nitrobenzyl alcohol, 100%). f I o n a b u n d a n c e s are expressed relative to the base peak m/z = 104 (diethanolamine, 75%).

9

J. Sokolowska-Gajda et al.

10

I ~O3H1-:-

I HN'-~°3H I

--

16. mlz 172

15. m/z 157

n

E. 1 HN - - ~ S O

3H

18. m/z 273

17. m/z 186

19. mlz 301 Fig. 9.

R e

Daughter ions (15-19) arising from the MS analysis of dye 8a.

30.

1 a

t

i

25

v e

A 20 b u tl

d

15 9;

a n c e

910

10

Be7

B4S 856 1367

850 Fig. 10.

B7

93e

9 B 900

950

1000 M/Z

F A B mass spectrum arising from heating a mixture of 4b and 5b.

Iron complexed formazan dyes

11

e~

.=_ ka

O 0

.=_ .E

12

J. Sokolowska-Gajda et al.

TABLE 3

Lightfastness of Some Experimental and Commercial Black Dyes Dye

Depth o f shade (%)

Lightfastness Wool 225.6 k J m 2

Nylon

451.2 k J m 2

225.6 k J m 2

451.2 k J m :

4b

2

3

2

1-2

1

13

6 2 6

5 3-4 4-5

4-5 2 4

4-5 1 4-5

3 1 3-4

20

2

1-2


<1

<1

6 2 6 2 6 2 6

4 12 5 3-4 4-5 2 4

3 <1 4 2-3 3-4 1 4

2-3 <1 2 4 4 1-2 <1

1 1 1 2 2 1-2 <1

21 CI Acid Black 52 CI Acid Black 172

at 2% and 6% d e p t h o f shade, a n d the dyeings were e v a l u a t e d for lightfastness, washfastness a n d c r o c k f a s t n e s s a c c o r d i n g to established p r o c e d u r e s f l Unlike 1:2 F e azo dyes which are usually olive-brown, b r o w n o r black, the synthesized 1:2 F e c o m p l e x e d f o r m a z a n dyes p r o d u c e violet a n d blue shades, a l o n g with blacks a n d browns. T h e dyeings o b t a i n e d h a v e very g o o d fastness p r o p e r t i e s (cf. T a b l e 2), a n d c o n t r a r y to o u r _e X

S02 NH2

H2N 02 S

X~ - - J ~

X 20

H

21

NHAc

Iron complexedformazan dyes

13

previously reported 1'2 1:2 Fe complexed azo dyes (20-21), they show very good lightfastness on nylon. The lightfastness of some of the black dyeings was also evaluated according to GM conditions42 for automotives and compared with commercial CI Acid Black 172. These results are given in Table 3. It is worthwhile mentioning that the formazan dyes containing sulfonic groups have low exhaustion from the dyebath, a property that could influence their utility.

EXPERIMENTAL The chemicals used in the synthesis of all dyes were obtained from Aldrich Chemical Company (Milwaukee, WI) or Mobay Chemical Company (Pittsburgh, PA), and were used without further purification. The purity of the synthesized dyes was checked by TLC (BuOH:Pyridine:H20 2:2:1), using glass-backed silica gel 60 plates from Bodman Chemical Company (Doraville, GA). The structure of all dyes was confirmed using IH N M R (unmetallized dyes) or negative ion FAB spectrometry (unmetallized and metallized dyes). JH N M R spectra were recorded on a GE Omega 500 MHz spectrometer, FAB mass spectra were recorded on a JEOL (Tokyo, Japan) HX 110 HF double-focusing mass spectrometer equipped with a FAB ionization source, and visible spectra were recorded using a Perkin-Elmer R-24A spectrophotometer in 50% EtOH/H20. Lightfastness, washfastness and crockfastness were evaluated according to AATCC Test Methods 16-1990, 61-1986 and 8-1985, respectively. 4~ In every case the rating scale employed ranged from a low of 1 to a high of 5.

Preparation of benzaldehydephenylhydrazone-4-sulfonamide 4-Aminobenzenesulfonamide (52 g, 0-3 mol) was dissolved in 200 ml H20 containing 30 ml 30% NaOH and added to 75 ml 4y NaNO2. The resulting solution was poured over 100 g crushed ice containing 100 ml 30% HC1 at a rate needed to maintain a reaction temperature of 5°C. The diazotization step was carried out for 40 min and the resultant diazonium salt was then added slowly to a stirred solution of 99-95 g Na2SO3 in 250 ml water at 10°C, and the reaction was continued for 1 h. At this point, the reaction temperature was raised to 70°C and 300 ml 30% HC1 was added over 30 min. The precipitated product was stirred overnight, collected by filtration, washed with cold water and dried. The phenylhydrazine-4-sulfonamide obtained (47 g) was dissolved in 600 ml H20 containing 40 ml 30% NaOH, and to this solution 27-5 g (0.26 mol) of benzaldehyde was added at 50-55°C. After stirring for 1 h, the temperature was reduced to 30°C and 24 ml 30%

14

J. Sokolowska-Gajda et al.

HC1 was added. The precipitated product was collected by filtration, washed with cold water and dried, to give 47.2 g of benzaldehyde phenylhydrazone4-sulfonamide (m.p. 199°C; lit43 m.p. 199°C). IH N M R (DMSO-d6, 500 MHz): 3 7-08, s, (2H), 3 7.13, d, (2H, J = 7.50), 3 7-32, t, (1H, J -- 7.50), 3 7.40, t, (2H, J = 7.00), ~ 7.65, d, (2H, J = 8.50); 7.68, d, (2H, J = 7.50), t~ 7.93, s, (1H), 3 10.80, s, (1H).

Preparation of benzaldehyde phenylhydrazone-4-sulfonic acid Sulfanilic acid (52 g, 0.3 mol) was dissolved in 200 ml H20 containing 16-5 g Na2CO 3. The resulting solution was cooled to 10°C and 35 g of c o n c . H2SO 4 was then added dropwise, followed by the addition of 75 ml 4N NaNO> The diazotization step was carried out for 15 min at 10-12°C. The diazonium salt was collected by filtration, washed with a small amount of cold water and added, at 5°C, to a stirred solution of 85 g of Na2SO 3 in 250 ml H20. After stirring the reaction mixture for 1 h, the temperature was raised to 95°C and 240 ml of concentrated n 2 s o 4 w a s added over a period of 30 min. The reaction mixture was left overnight and the precipitated product was collected, washed with cold water and dried. The phenylhydrazine-4-sulfonic acid obtained (52 g) was dissolved in 500 ml H20 containing 60 ml 30% NaOH, and 30 g (0.28 mol) of benzaldehyde was added at 50-55°C. Stirring was continued for 1 h, the temperature was reduced to 30°C, and the product was precipitated by acidification with 36 ml 30% HC1. The product was collected, washed with a small amount of cold water and dried, to give 50 g of benzaldehyde phenylhydrazone-4-sulfonic acid. IH N M R (DMSO-d6, 500 MHz): 8 6.98, d, (2H, J = 8-83), ~ 7.30, t, (1H, J = 7.35), ~ 7.39, t, (2H, J = 7.35), ~ 7.45, d, (2H, J = 7.35), ~ 7.65, d, (2H, J = 7.35), ~ 7.87, s, (1H), 8 10.44, s, (1H).

Preparation of dyes 2a and 2b A solution of 9.90 g (0.05 mol) 1-hydroxy-2-aminobenzene-4-sulfonamide in 100 ml H20 containing 6.25 ml 30% NaOH was poured over a mixture of 75 g crushed ice and 14-5 ml 30% HC1. To the resulting suspension, 12.5 ml 4N NaNO2 was added at a rate such that the reaction temperature was kept at 0-5°C. Diazotization was carried out for 1 h, and the'solution of the diazonium salt was added dropwise at 0-5°C to 10.59 g (0.054 mol) benzaldehyde phenylhydrazone dissolved in 125 ml H20 containing 75 ml pyridine and 25 ml 30% NaOH. The coupling reaction was stirred overnight and the intermediate unmetallized dye (2a) was salted out of solution, using 15% NaC1, to give 11 g of violet product.

Iron eomplexedformazan dyes

15

1H N M R (DMSO-d6, 500 MHz): 6 7.08, d, (1H, J = 8.82), 6 7.30-7.33, m, (3H), 6 7.40, t, (1H, J = 7.35), 6 7.50, m, (3H), 6 7.60, t, (2H, J = 7.35), 6 7-88, d, (2H, J -- 8-82), 6 8.13, d, (2H, 7.35), 6 8.27, m, (1H), 6 11.48, s, (1H), 6 15.68, s, (1H). Visible spectrum: ~rnax = 496 nm, e = 8,600. The unmetallized formazan dye was dissolved in 140 ml H20 containing 2.2 ml 30% NaOH and warmed to 50°C. Then, 3.86 g (0.0139 mol) FeSO4.7H20 dissolved in 20 ml H20 was added and the reaction was stirred for 2 h at 60-70°C, monitoring by TLC, using BuOH:pyridine:H20 2:2:1 as the eluent. At this point, dye 2a (Rf = 0.96) was fully converted to the desired 1:2 complex 2b (Rf = 0.84). Visible spectrum: Amax= 512 nm, e -- 14,200.

Preparation of dyes 3a and 3b 2-Amino-4-chlorophenol (7.175 g, 0.05 mol) was dissolved in 80 ml H20 containing 10 ml 30% HCI, and after cooling the solution to 0-5°C, diazotization was accomplished with the aid of 12.5 ml 4 Y NaNO2. After stirring for 30 min, the diazonium salt obtained was added, at 0-5°C, to a solution of 14-75 g (0-054 mol) of benzaldehyde phenylhydrazone-4sulfonamide, 25 ml 30% NaOH, and 30 ml pyridine in 350 ml H20. The coupling reaction was stirred overnight, and the unmetallized dye (3a) was salted out of solution, using 15% NaCI, giving 24 g of a reddish-blue product. IH N M R (DMSO-d6, 500 MHz): 6 7.08-7.16, m, (2H), 6 7.34-7-41, m, (2H), 6 7.47, t, (1H, J -- 7-50), 6 7.56, s, (2H), 6 7.70-7-89, m, (4H), 6 8.05, m, (1H), 6 8-15, d, (2H, J = 8.82), 6 10.30, bs, (1H), 6 15.14, s, (1H). Visible spectrum: Amax= 503 nm, e = 6,700. The unmetallized formazan dye was dissolved in 280 ml H20 containing 4.4 ml 30% NaOH, and metallized using 6.95 g (0-025 mol) FeSO4.7H20 dissolved in 40 ml H20. The reaction was stirred for 2 h at 60-70°C. At this point, dye 3a (Rr = 0-82) was fully converted to its 1:2 Fe complex 3b; (Rf -- 0.67). The target 1:2 Fe complex was salted out of solution, using 5% NaCI, to give 18-4 g of the dye. Visible spectrum:/~max • 553 rim, e -- 13,850.

Preparation of dyes 4a and 4b 2-Amino-4-nitrophenol (7-70 g, 0.05 mol) was dissolved in 75 ml H20 containing 10 ml 30% HCI and, after cooling to 0-5°C, was diazotized with 12.5 ml 4N NaNO2. Diazotization was carried out for 45 min and the diazonium salt obtained was added, at 0-5°C, to a solution of 14.75 g (0.054 mol) benzaldehyde phenylhydrazone-4-sulfonamide and 25 ml 30% N a O H in 350 ml H20 and 30 ml pyridine. The coupling reaction was stirred overnight. The unmetallized dye (4a) was salted out of solution using 15% NaC1 to give 21.4 g of reddish-blue product.

16

J. Sokolowska-Gajda et al.

IH N M R (DMSO-d6, 500 MHz): 6 7-22, d, (1H, J = 9.13), 6 7.40-7.45, m, (3H), 6 7.52, t, (2H, J -- 7.99), 6 7.84, d, (2H, J = 7.99), 6 7-96, d, (2H, J = 9-13), 6 8.08, d, (2H, J = 7.99), 6 8.15, dd, (1H, J = 3.42, J = 9.13), 6 8.57, d, (1H, J = 3-42), 6 12.30, bs, (1H), 6 15.19, s, (1H). Visible spectrum:/~max -- 553 nm, e = 10,200. Dye 4a was dissolved in 280 ml H20 containing 4.4 ml 30% NaOH, at 50°C, and metallized using 6.95 g (0-025 mol) FeSO4-7H20 dissolved in 40 ml H20. The reaction was stirred for 2 h at 60-70°C. At that point, dye 4a ( R f = 0"85) was fully converted to 1:2 Fe complexed dye 4b (Rf -- 0.79). The target 1:2 Fe formazan complex was salted out of solution, using 5% NaCI, to give 22-5 g dye. Visible spectrum: /~rnax = 494 nm, e -- 17,535; 500 nm (sh).

Preparation of dyes 5a and 5b A solution of 5.45 g (0.05 mol) of 2-aminophenol in 350 ml H20 containing 5 ml 30% NaOH and 12.5 ml 4 Y NaNOz was poured over 16 g of crushed ice containing 16-6 ml 30% HC1. Diazotization was carried out for 30 min at 0-5°C. The resulting diazonium salt was added dropwise, at 0-5°C, to a solution of 14-75 g (0.054 mol) of benzaldehyde phenylhydrazone-4sulfonamide and 25 ml 30% NaOH in 350 ml H20 and 30 ml pyridine. The coupling reaction was stirred overnight. The unmetallized dye 5a (R~ = 0-83) was salted out of solution, using 15% NaC1 to give 15-4 g of red product. ~H N M R (DMSO-d6, 500 MHz): 6 7.20, t, (1H, J = 7.81), 6 7.45, t, (1H, J = 7.81), 6 7.51, t, (2H, J = 7-81), 6 7.58, bs, (2H), ~ 7.71, t, (2H, J = 7.81), 6 8.00-8.03, m, (3H), 6 8.12, d, (2H, J = 7.81), 6 8.25, d, (1H, J = 7-81), 6 8.32, d, (1H, J = 7.81), 6 13.70, bs, (1H), 6 15-34, s, (1H). Visible spectrum: /~rnax ---- 474 nm, e -- 11,670; 570 nm (sh).

Preparation of dyes 6a and 6b Anthranilic acid (6.85 g, 0-05 mol) was dissolved in 75 ml H20 containing 3 g Na2CO3, at 40°C, and 15 ml 30% HC1 was added. The reaction mixture was cooled to 0°C and diazotized with 12.5 ml 4 N NaNO2. Diazotization was carried out for 3 min at 0-2°C. The diazonium salt obtained was added, at 0-5°C, to a solution of 14.75 g (0.054 mol) of benzaldehyde phenylhydrazone-4-sulfonamide and 25 ml 30% NaOH in 350 ml H20 and 30 ml pyridine. The reaction mixture was stirred overnight, and the unmetallized dye (6a; Rf = 0.7) was isolated by acidification with 40 ml 30% HC1, to give 21-2 g of reddish-orange product. IH N M R (DMSO-d6, 500 MHz): 6 7.19, t, (1H, J = 7-81), 6 7.43, t, (1H, J -- 7.81), ~ 7.51, t, (2H, J = 7.81), 6 7.59, bs, (2H), 6 7-72, t, (1H,

Iron complexedformazan dyes

17

J = 7.81), 8 8.00-8.15, m, (5H), 8 8.23-8.33, m, (3H), 8 13.67, bs, (1H), 8 15.34, s, (1H). Visible spectrum: Amax= 474 nm, e = 11,285. The unmetallized formazan dye was dissolved at 50°C in 280 ml H20 containing 4.4 ml 30% N a O H and metallized with 6.95 g (0.025 mol) FeSO4-7H20 dissolved in 40 ml H20. The reaction was stirred for 2 h at 60-70°C. The target 1:2 Fe complex 6b ( R f = 0"6) was salted out of solution, using 5% NaC1, to give 22.5 g dye. Visible spectrum: /~max ---- 551 rim, e = 7,200, A~ax = 586 nm, e' = 7,500.

Preparation of dyes 7a and 7b Diazotization was carried out as described above for the synthesis of dye 3a, and the resulting diazonium salt was coupled with benzaldehyde phenylhydrazone-4-sulfonic acid dissolved in 300 ml H 2 0 containing 25 ml 30% N a O H and 30 ml pyridine, under the conditions employed with the synthesis of 4a. The unmetallized dye 7a (Rf = 0.69) was salted out of solution with 15% NaC1 to give 19.8 g product. ~H N M R (DMSO-d6, 500 MHz): 8 7.13, d, (1H, J = 9.00), 8 7.72, dd, (1H, J = 3.00, J = 9.00), t5 7.77, t, (2H, J = 7.50), t5 7.82, t, (1H, J = 7.50), 8 7.85-7.92, m, (4H); 8 8.01, s, (1H), 8 8.32, d, (2H, J = 7-50), ~ 12.15, s, (1H), 8 15.34, s, (1H). Visible spectrum: Areax = 506 nm, e = 7,000. The target unmetallized dye 7b (Rf = 0.52) was synthesized and isolated in the manner described for 6b, giving 17.5 g product. Visible spectrum: '~max ---550 nm, e -- 12,700.

Preparation of dye 8b Using the procedure described above for the synthesis of dyes 4b and 7b, 20 g of dye 8b was obtained. 1H N M R of 8a (DMSO-d6, 500 MHz): 8 7.05, d, (IH, J = 8 " 8 2 ) , t~ 7"42, t, (1H, J = 7"36), 8 7"52, t, (2H, J = 7"36), 8 7"85, d, (2H, J = 7"36), 8 8"12, d, (2H, J = 8 . 8 2 ) , t~ 8.32, d, (2H, J = 7.36), 8 8.38, dd, (1H, J -- 2.94, J = 8.82), 8 8.55, d, (1H, J = 2.94), 8 12.99, bs, (1H), 8 15.48, s, (1H). Visible spectrum of 8a: Ama x -- 550 nm, e = 9,800. Visible spectrum of 8b: )tma x = 502 nm, e = 17,800; 510 nm (sh). Rf 8a = 0.67 (BuOH:pyridine:H20/2:2:l). R r 8b = 0.52.

Preparation of dye 9b Using the procedure employed in the synthesis of dyes 6b and 7b, 22-5 g dye 9b was obtained. ~H N M R of 9a (DMSO-d6, 500 MHz): 8 7.12, t, (1H, J -- 7.35), 8 7-43, t,

18

J. Sokolowska-Gajda et al.

(1H, J = 7-35), 6 7.51, t, (2H, J = 7.35), 6 7.68, t, (1H, J = 7.35), 6 7.80, d, (2H, J = 7.82), 6 7.99, d, (1H, J = 7.35), a 8.10, d, (2H, J = 7.35), 8 8.17 8.22, m, (3H), ~ 13.50, bs, (1H) 8 15.12, s, (1H). Visible spectrum of 9a: Amax = 465 nm, e -- 13,200. Visible spectrum of 9b: Areax = 556 nm, e -- 7,100; A~ax = 583 nm, e = 7,200. Rf 9a = 0.68 (BuOH:pyridine:H20/ 2:2:1). Rf9b = 0.61.

Preparation of dye 10 A mixture of 10 g (0.025 mol) dye 2a and 9-85 g (0.025 mol) dye 5a was dissolved at 50°C in 275 ml H20 containing 4.4 ml 30% NaOH and metallized with 6-95 g (0.025 mol) FeSOn.7H20 dissolved in 40 ml H20 over 2 h at 60-70°C. The target 1:2 Fe complex was salted out of solution using 5% NaC1 to give 18.65 g product, which was a statistical mixture of dyes 10, 2b, and 5b. Rf of the major dye (10) = 0.52.

Preparation of dye 11 A mixture of 10 g (0.025 mol) dye 2a and 10.75 g (0.025 mol) dye 3a in 275 ml H20 containing 4.4 ml N a O H was metallized with 6.95 g (0.025 mol) FeSOa.7H20 dissolved in 40 ml H20 over 2 h at 60-70°C. The 1:2 Fe complex was salted out of solution with 5% NaC1 to give a statistical mixture of dyes 11, 2b, and 3b. Rf of the major dye (11) = 0.72.

Preparation of dye 12 A solution of 10.75 g (0.025 mol) dye 3a and 9.85 g (0.025 mol) dye 5a in 275 ml H20 containing 4.4 ml NaOH was metallized in the way described previously for 5b. The 1:2 Fe complex was isolated by salting it out of solution with 5% NaCI, giving 20 g of product which was a statistical mixture of dyes 12, 3b, and 5b. Rf of the major dye (12) -- 0.75.

Preparation of dye 13 A solution of 11 g (0-025 mol) dye 4a and 10.75 g (0.025 mol) dye 3a in 275 ml H20 with 4-4 ml 30% NaOH at 50°C was metallized in the way described previously for 4b. The 1:2 Fe complex containing 13, 3b, and 4b was salted out of solution with 5% NaC1, giving 15-6 g of product. Rf of the major dye (13) = 0.63.

Iron complexedformazan dyes

19

Preparation of dye 14 The synthesis was similar to those described for dyes 13 and 7b. This afforded 16.5 g of a statistical mixture of dyes 14, 7b and 8b. Rf of the major dye (14) = 0.53.

CONCLUSIONS The results of this investigation demonstrate that it is possible to prepare 1:2 Fe complexed formazan dyes having good affinity for protein and polyamide fibers. It is worthwhile noting that such dyes expand the spectrum of colors traditionally reported as arising from Fe complexes to include examples of violet and blue colors. The above results also demonstrate that it is possible to synthesize acid black dyes based on the formazan system whose fastness properties compare favorably with those of currently used commercial acid black dyes. Moreover, it is also suggested that the results of this study provide further evidence for the idea that the use of Fe salts as metallizing agents provides a potential solution to the environmental problems associated with the synthesis and application of Cr- and Co-based metallized acid dyes.

ACKNOWLEDGEMENT The authors wish to thank the National Textile Center for providing the financial support for this investigation.

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Nippon Kayaku Co., Japanese Patent 60226559 (1985). Nippon Kayaku Co., Japanese Patent 60258266 (1985). BASF, German Patent 3840653 (1990). BASF, European Patent 315045 (1989). BASF, European Patent 315046 (1989). Ciba-Geigy, European Patent 228348 (1987). Bayer, German Patent 3743236 (1989). Bayer, German Patent 3239364 (1984). Bayer, German Patent 3406232 (1985). Bayer, German Patent 4005122 (1991). Bayer, European Patent 338310 (1989). Hoechst, German Patent 3326638 (1985). Hoechst, German Patent 3153413 (1985). Hoechst, German Patent 3440265 (1986). Hoechst, German Patent 3843135 (1990). Hoechst, US Patent 4607098 (1986). Ciba-Geigy, European Patent 410930 (1991). Ciba-Geigy, European Patent 410931 (1991). E. I. du Pont de Nemours & Company, US Patent 3592584 (1971). E. I. du Pont de Nemours & Company, US Patent 3663525 (1972). Toms River Chemical Corp., US Patent 1275877 (1972). Toms River Chemical Corp., US Patent 3655637 (1972). Durand & Huguenin, A. G., US Patent 3497493 (1970). Fierz-David, H. E. & Blangey, L., Fundamental Processes of Dye Chemistry. Interscience Publishers, New York, London, 1949, pp. 128-9. Barber, M. N., Bordoli, R. S., Sedgwick, R. D. & Tyler, A. N., J. Chem. Soc. Chem. Commun., 7 (1981) 325. Freeman, H. S., Hao, Z., Sokolowska-Gajda, J., van Breemen, R. B. & Le, J., Dyes and Pigments, 16 (1991) 317. Shimanskas, C., Ng, K. & Karlinger, J., J. Rap. Commun. Mass Spectrom., 3(9) (1988) 300. Meili, J. & Seibl, J., Org. Mass Spectrom., 19 (1984) 581. Sweetman, B. J. & Blair, T. A., Biomed. and Environ. Mass Spectrom., 17 (1988) 337. Freeman, H. S., van Breeman, R. B., Esancy, J. F., Ukponmwan, D. O., Hao, Z. & Hsu, W.-N., Text. Chem. Color., 22(5) (1990) 23. Technical Manual of the American Association of Textile Chemists and Colorists, Vol. 67, 1992. Bulluck, J. E. & Garrett, D. L., J. Ind. Fabrics, 4(2) (1985) 23. Willstaed, H., Svensk Kern. Tidskr., 55 (1943) 214, 219.